WARP Project Forums - Wireless Open-Access Research Platform

You are not logged in.

#1 2017-Feb-07 16:09:38

zhimeng
Member
Registered: 2015-Sep-30
Posts: 47

Set arbitrary center frequency

Hi.
Our goal is to set the 802.11 reference at arbitrary center frequency, different from the standard 802.11 frequencies, such as channel 1,2 or 4.

Based on https://warpproject.org/trac/wiki/cores … ontroller, we think that it is possible to set the center frequency to any value.

So we modified the radio_controller.c file, by modifying these parameters rc_tuningParams_24GHz_freqs, rc_tuningParams_24GHz_reg3, rc_tuningParams_24GHz_reg4. Currently, we just switched the order of these parameters to test if this works, but didn't observe the change of center frequency.


Could you shed some light onto this?

Thanks so much for your help!

Offline

 

#2 2017-Feb-07 16:37:38

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: Set arbitrary center frequency

Modifying radio_controller.c is the correct way to change the MAX2829 tuning parameters. However, because the radio_controller driver is part of the BSP, you must modify the original radio_controller.c file in the edk_user_repository and re-build the entire BSP. Modifying the source file in the SDK via the BSP libsrc folder will not trigger re-compilation of the BSP, so your changes will not be included in the compiled software application.

- Navigate to your local edk_user_repository/WARP/pcores/radio_controller_axi_v3_01_a/src/
- Make your changes to radio_controller.c
- In the SDK right-click on the DCF or NoMAC projects and select "Clean Project"; wait for the compilation to finish
- Verify your updated code appears in wlan_bsp_cpu_low/mb_low/libsrc/radio_controller folder

Offline

 

#3 2017-Feb-07 16:39:36

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: Set arbitrary center frequency

I forgot to add that we wrote a small Python script to help calculate the PLL register values for given center frequencies. This script is in the repository: max2829_pll_tune_val_gen.py. We used this script to generate the rc_tuningParams arrays you mentioned above.

Offline

 

#4 2017-Feb-07 17:03:29

zhimeng
Member
Registered: 2015-Sep-30
Posts: 47

Re: Set arbitrary center frequency

Hi.
We have modified following your suggestions, and now we have the new radio_controller.c file in the project.
Thanks a lot!

Offline

 

#5 2018-Jan-09 21:46:15

zhimeng
Member
Registered: 2015-Sep-30
Posts: 47

Re: Set arbitrary center frequency

Hi!
We are now trying to move the central frequency to 2.66GHz following the same method.
(1) We used the aforementioned method to generate the  rc_tuningParams_24GHz_reg3, rc_tuningParams_24GHz_reg4, and then changed the radio_controller.c in edk_user_repository/WARP/pcores/radio_controller_axi_v3_01_a/src/. Then we cleaned and rebuilt the project
(2) When the central frequency is legacy, we can use WARP to receive packets correctly from USRP. However, when we changed the central frequency of WARP and USRP to 2.66Ghz, WARP could not receive the packets from USRP. We can change the USRP central frequency and have verified that.
(3) In the max2829_pll_tune_val_gen.py, it says 'Python code to generate arrays of PLL tuning register values for MAX2829'. We searched the manual of MAX2829, while the manual says 2.4-2.5Ghz. Does this suggest we could not change the central frequency to 2.66ghz?
Thanks so much in advance

Offline

 

#6 2018-Jan-09 22:37:21

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5159

Re: Set arbitrary center frequency

(3) In the max2829_pll_tune_val_gen.py, it says 'Python code to generate arrays of PLL tuning register values for MAX2829'. We searched the manual of MAX2829, while the manual says 2.4-2.5Ghz. Does this suggest we could not change the central frequency to 2.66ghz?

Correct - the MAX2829 supports tuning in the 2.4-2.5GHz and 4.9-5.875GHz ranges.

Offline

 

#7 2018-Jan-09 23:21:19

zhimeng
Member
Registered: 2015-Sep-30
Posts: 47

Re: Set arbitrary center frequency

Thanks so much for your help!

Offline

 

Board footer